public void CalculateTotalSquareAreas()
        {
            // Arrange
            const double expectedResult = 40;

            List <Square> squares = new List <Square>
            {
                new Square()
                {
                    Side = 2
                },
                new Square
                {
                    Side = 6
                }
            };

            _squareRepository.Setup(m => m.GetAll()).Returns(squares);

            SquareCalculator calculator = new SquareCalculator(_squareRepository.Object);

            // Act
            var result = calculator.GetSumCalculatedAreas();

            // Assert
            result.Should().BeApproximately(expectedResult, ExpectedPrecision);
        }